Process for moisture-proofing metals

ABSTRACT

A PROCESS FOR RENDERING METAL SURFACES WATER REPELLENT, ESPECIALLY PARTICULATE METALS AND POROUS METAL BRIQUETTES OR SIMILAR AGGREGATE STRUCTURES, INCLUDING, PARTICULARLY, CHEMICALLY ACTIVE FERROUS METALS AS RESULTANT FROM DIRECT IRON ORE REDUCTION PROCESSES. SUCH BRIQUETTES OR POWDERS, WHILE HOT, ARE IMMERSED, DRIPPED, SPRAYED, OR OTHERWISE CONTACTED WITH ADMIXTURES OF CERTAIN KINDS OF OLEFINS, CONTAINED IN CRITICAL CONCENTRATIONS WITHIN THE ADMIXTURE. SUITABLY, THE OLEFIN ADMIXTURE CONTAINS POLYENES AND DIENES, PREFERABLY CYCLOPOLYENES AND CYCLODIENES. THE BRIQUETTES OR POWDERS ARE CONTACTED WITH THE OLEFIN ADMIXTURES RANGING FROM ABOUT 300*F. TO ABOUT 700*F., OR HIGHER, AND MORE PARTICULARLY AT FROM ABOUT 400*F. TO ABOUT 600*F., AT TIMES SUFFICIENT TO INDUCE PENETRATION OF THE OLEFINS INTO THE PORES AND CREVICES OF THE METALLIC SURFACES. THE CONTACT TIME AND SURFACE TEMPERATURE OF THE METAL ARE THUS CONTROLLED, AND THE TEMPERATURE OF THE OLEFINIC MIXTURE IS NOT PERMITTED TO RISE TO MORE THAN ABOUT 300*F. THE OLEFINS PENETRATE INTO THE CAPILLARIES AND CREVICES OF THE METAL PARTICLES, EVAN WHEN THE PARTICLES HAVE BEEN COMPACTED INTO DENSE MASSES SUCH AS BRIQUETTES, SUFFICIENT WHEN CURED TO PRODUCE DISCONTINUOUS HYDROPHOBIC RESINOUS DEPOSITS WHICH RENDER BOTH OUTER AND INNER METAL SURFACES WATER REPELLENT.

United States Patent 3,573,959 PROCESS FOR MOISTURE-PROOFING METALS Marnell A. Segura, Edwin E. Sale, and John C. Winkler,

Baton Rouge, La., assignors to Esso Research and Engineering Company No Drawing. Filed Feb. 5, 1969, Ser. No. 796,918 Int. Cl. 344d 1/06, 1/46 U.S. Cl. 117-37 17 Claims ABSTRACT OF THE DISCLOSURE A process for rendering metal surfaces Water repellent, especially particulate metals and porous metal briquettes or similar aggregate structures, including, particularly, chemically active ferrous metals as resultant from direct iron ore reduction processes. Such briquettes or powders, while hot, are immersed, dripped, sprayed, or otherwise contacted with admixtures of certain kinds of olefins, contained in critical concentrations within the admixture. Suitably, the olefin admixture contains polyenes and dienes, preferably cyclopolyenes and cyclodienes. The briquettes or powders are contacted with the olefin admixtures ranging from about 300 F. to about 700 F., or higher, and more particularly at from about 400 F. to about 600 F., at times suflicient to induce penetration of the olefins into the pores and crevices of the metallic surfaces. The contact time and surface temperature of the metal are thus controlled, and the temperature of the olefinic mixture is not permitted to rise to more than about 300 F. The olefins penetrate into the capillaries and crevices of the metal particles, even when the particles have been compacted into dense masses such as briquettes, sufficient when cured to produce discontinuous hydrophobic resinous deposits which render both outer and inner metal surfaces water repellent.

Various techniques are known for producing metal powders and porous aggregates, including particularly ferrous metals. It is thus known to produce reduced iron products by direct reduction of ores, e.g., oxidic iron ores or ores consisting essentially of iron oxides. The ore is often reduced while it is in fluidized condition by direct contact with gases at elevated temperatures below the sintering or fusion temperature of the ore. In advanced processes of this general type, fluidized beds of ore are staged as separate reduction zones and the ore is progressively reduced. For example, hematite ore, or ferric oxide, is charged to a first fluidized bed, or beds, and the oxide is reduced with, e.g., hydrogen or carbon monoxide, or both, to form magnetic oxide of iron (magnetite). In a subsequent bed, or beds, the magnetic oxide of iron is further reduced to ferrous oxide (wustite). Finally, the ferrous oxide is further reduced in another bed, or beds, to provide metallized products ranging often from about 80 to about 95 percent metallic iron.

The problems associated with moisture pick-up by the metal products are particularly severe. Such products are thus characterized as having relatively high surface area and high porosity. These properties create a high affinity for the products to pick up moisture. The products also possess a high chemical activity, or tendency to reoxidize or back-oxidize, especially in the presence of moisture. The acute tendency of the product, e.g., iron powder, to pick up moisture coupled with its propensity to chemically react and back-oxidize in the presence of moisture creates acute and difficult problems. Even when the metal is compacted at relatively high temperatures and pressures, these properties are retained. So also, unfortunately, are the burdensome problems due to the presence of moisture. Briquettes produced from such particulate iron products are thus characterized as having high surface area, high porosity and, as well, high internal voids. They are, in fact, sponge-like in character. The presence of moisture in these products not only produces back-oxidization, but presents a hazard when charged into high temperature furnaces for further processing, e.g., as in steelmaking. The mechanical shock produced is acute. Sputtering and spattering of the intensely hot melt occurs. Reactions can be sufliciently violent that melt is thrown from the furnace, and furnace linings can be damaged. The loss of heat produced by volatilization of the water is quite burdensome, and represents an economic debit.

For these and other reasons, the particulate metals are often coated or provided with surface films to provide impregnable surface barriers. Powders are sometimes admixed with various additives and binders and then compacted. The aggregates themselves, after formation, are sometimes coated or provided with surface films. This decreases, to some extent, exposure area, lessens moisture pick-up and reduces chemical activity. Back-oxidization is suppressed. In general, however, the very presence of the film, binder, or additive is undesirable, adds nothing to the end use for which the product was created, and constitutes an impurity introduced into the metals. Even where the impurities introduced into the iron or steelmaking process can be eliminated, the noxious fumes which are produced prove quite disagreeable, troublesome and often produce health hazards. The presence of these additives is thus generally burdensome, undesirable and and often intolerable. This is particularly so where it is desired to use the product as a free flowing high purity iron powder, as in electric furnace steelmaking.

These problems present a dilemma to the potential user of the products. In the presence of corrosive gases, fumes, impurities, but particularly in the presence of spray and atmospheric moisture, there is an acute tendency for the reduced iron product to pick up these and other undesirable contaminants and back-oxidize, this to the chagrin of potential users who desire, inter alia, a highly metallic product. The maintenance of a sterile environment to completely protect the metal is entirely impractical.

Accordingly, it is the primary objective of the present invention to supply this need, or to obviate the foregoing and other disadvantages. In particular, it is an object to provide a process for rendering metal surfaces, espe cially ferrous metal surfaces, water repellent. A specific object is to provide a process for the protection of ferrous metals produced by direct reduction processes, especially processes which provide chemically active metals with relatively large surface areas, which will not prove obnoxious in steelmaking by substantial evolution of smoke and flame.

These and other objects are achieved in accordance with the present invention which comprises a process for moisture proofing metals by contact at selected conditions with olefins, and admixtures of certain kinds of olefins contained in critical concentration with the admixture, at temperature and time conditions sufficient to induce penetration of the olefins into the capillary pores and crevices of the metals. On curing, the olefins produce discontinuous hydrophobic resinous deposits which render the metals Waterrepellent. The initial step of the process contemplates immersing, dipping, spraying or other- Wise contacting metal surfaces, particularly powders or porous metal briquettes, and more especially chemically active metals such as produced in direct iron ore reduction processes, with admixtures of certain kinds of olefinic liquid hydrocarbons. The admixture contains ethylenically unsaturated hydrocarbons, particularly dimers, trimers, tetramers and including, for effective results, polyenes and dienes.

The liquid olefin hydrocarbon comprises acylic and cyclic olefins, diolefins, triolefins, especially dimers, trimers, and tetramers of such olefins. Especially suitable are olefin admixtures of such compounds which contain dimers, trimers, and tetramers of cyclopolyenes and cyclodienes. For best results, the admixture should contain from about 2 percent to about 15 percent, and preferably from about 5 percent to about percent polyenes or dienes, or both, based on the total weight of olefins in admixture. Preferably, the dienes are cyclodienes. Suitable mixtures can be formed by admixing commercial products and residuals. For example, suitable olefinic liquid hydrocarbon mixtures can be obtained by admixing polyenes or dienes, or both, with commercially available olefinic liquid hydrocarbons such as obtained by steam cracking naphthas to obtain olefinic mixtures, which are then partially polymerized over hot clay. The source of polyenes or dienes, itself, can also be a commercial mixture. The resultant olefinic hydrocarbon mixture employed consists generally of olefins, diolefins, polyolefins, dimers, trimers, tetramers, and the like, of average carbon number ranging from about C to about C and more particularly from about C to about C Briquettes, or powders, at elevated temperatures are immersed, dipped, sprayed or otherwise contacted with the olefin or olefinic mixtures, dried and then cured to produce hydrophobic, discontinuous, resinous or resinlike deposits within the capillary pores and crevices, this rendering the so-treated metals impervious to penetration, especially by moisture, and hence resistant to further change upon exposure to various environments which tend to produce back-oxidation. The treated metals thus become highly impervious to attacks by noxious gases, fumes, liquids and other materials, and particularly resistant to penetration by moisture, water or other aqueous media.

The briquettes or metal powders are contacted with the olefinic liquid hydrocarbons while the latter are maintained at temperatures sufiicient to induce limited penetration by the olefinic hydrocarbons into the capillary pores and crevices of the metal, without substantially decomposition of the said olefinic liquid hydrocarbons. Suitably, the temperature of the metal surface during initial contact ranges from about 300 F. to about 700 F., and preferably from about 400 F. to about 600 F. Temperatures within this range produce better and more durable penetration of the pores with less olefins being required. There is little or no advantage in maintaining temperatures above about 700 F. for moisture-proofing. On the other hand, temperature below about 400 F. are unsatisfactory inasmuch as a film is formed which does not penetrate and which produces excessive quantities of smoke-forming resins. Moreover, the products are sticky, which is particularly undesirable for many uses of metal powder. Furthermore, below this temperature, excessive amounts of olefins are absorbed. Internal temperatures can exceed these temperatures. The contact time of the metal is not sufficiently long to produce decomposition of the heat reactive olefinic liquid hydrocarbon. Olefin temperatures greater than about 300 F. are generally unsatisfactory inasmuch as vapor losses of olefins are excessive. Preferably, olefin temperatures should not exceed about 200 F. On the other hand, at temperatures below about 150 F., the olefins are too viscous for effective penetration. Witht diluted solutions, lower temperatures are satisfactory.

The viscosity of the liquid olefin hydrocarbon preferably ranges from about 100 SSU (ASTM D-8-53) to about 250 SSU, and preferably from about 150 SSU to about 230 SSU, and can be readily controlled, if desired, by incorporation of solvents. The liquid olefin hydrocarbon is readily soluble in aromatic, paraffinic, and chlorinated hydrocarbons, acetates, ketones and relatively high molecular weight alcohols. Dialkyl sulfoxidcs, e.g., dimethyl sulfoxide, have been found particularly useful as solvents, penetration of the olefin hydrocarbons into the pores and crevices of the metals being achieved quite rapidly and efiiciently. Driers can also be added, if desired. Suitable driers are, e.g., iron tallate, iron naphthanate, iron oxide, manganese oxide, and the like.

Contact time is to some extent dependent on the temperature of both the metal and olefinic hydrocarbon. During immersion or dipping, e.g., the temperatures of both are controlled by contact time, but to a large measure these variables also control the extent of penetration and ultimate formation of durable resin-like deposits within the capillary pores and crevices. Film formation is to be avoided, as well as excessive penetration of the olefin hydrocarbon into the metal. On the other hand, penetration must be sutficient to seal the pores and crevices, and the sealing must be adequate to withstand environmental factors and conditions. Suitable contact times between the metal and olefin for achieving proper penetration into the capillaries and crevices, at specified temperatures, ranges generally from about 5 to about 30 seconds, and preferably from about 5 to about 20 seconds. After such contact from about 10 to about 30 seconds are allowed for excess olefin to drip from the metal surfaces.

The residual heat left in the hot metal after contact and withdrawal from the liquid olefin hydrocarbons is sometimes adequate to effect drying and curing to cause the formation of resinous deposits within the capillary pores and crevices of the metal. In any event, some degree of curing will be effected and, over a sufficient period of time, will be completed. Curing can readily be completed within from about 5 to about 60 minutes, and generally from about 15 minutes to about 45 minutes, by contact with air, preferably at temperatures ranging from about 50 F. to about 300 F. and, more preferably, from about 70 F. to about 200 F. The surface of the metal is thus dried, cooled, and then cured by natural or forced air convection.

In the early or initial withdrawal of the metals from the reduction reaction stages, the metals are normally first cooled from reduction temperatures by contact with inert gases, mild reducing or oxidizing gases, a spray of water or steam, and cooled to immersion, dip or contact temperature. In accordance with a preferred embodiment, metallic iron from a direct iron ore reduction process, can be simultaneously quenched and moisture-proofed. Pursuant thereto, briquettes or iron powder, at reduction temperatures ranging from about 1000 F. to about 1800 F., and preferably from about 1400 F. to about 1600 F., can be contacted with an aqueous emulsion or dispersions of the olefins. Oil-in-water or -water-in-oil emulsions are satisfactory. Such emulsions are formed by admixing from about 20 percent to about percent, and preferably from about 40 to about 60 percent, of the olefin hydrocarbon with water or other aqueous media, based on the weight of the emulsion. The intensely hot metallic iron is then dipped, sprayed or otherwise contacted with the emulsion at very short contact times, ranging from about 0.5 second to about 30 seconds, and preferably from about 1 second to about 10 seconds, to reduce the temperature of the metal to below about 600 F., and preferably below about 500 F., after which time the metal surfaces are drained of excess liquid and further cooled and cured by contact with ambient air, or by natural or forced air circulation.

Pursuant to the practice of this invention, even particulate metal or powders, which contain carbon in concentrations ranging from about 1 percent to as high as 8 percent or more can be effectively moisture-proofed, and then compacted or pressed into briquettes which are substantially moisture-proof. Heretofore, briquettes formed from such high carbon content powders were too porous for practical use.

A key and novel feature of this invention resides in the very nature, manner of deposition, and formation of the resin-like material within the capillary pore surfaces and crevices. Effective concentrations range only from about 0.05 percent to about 0.7 percent of the deposited resinous or resin-like material, and results are generally optimum at concentrations ranging from about 0.1 percent to about 0.3 percent, based on the total weight of impregnated metal. It is indeed amazing that such minute amounts of deposited material can function so effectively in preventing moisture penetration.

Applicants, while they do not desire to be bound by specific theory, believe that the relatively widely dispersed resinous deposits are effective only in part because surface pores and crevices are sealed. More importantly, highly efficient and effective moisture-proofing is achieved because of a screening effect of hydrophobic centers which repels moisture. A moisture-repelling force is exerted by the sum-total of the hydrophobic centers, due to surface tension. The screening force referred to repels, but in effect acts much as a wire screen used to extract water contaminant from gasoline which is passed through the wire mesh. In the latter, water molecules, despite their infinitesimal size, are attracted to the screen wire and held thereon because of the higher affinity of the water molecules for the wire than for other water molecules. In the instant invention, the screen of hydrophobic centers has low affinity for and repels moisture. Water has greater afiinity for itself than for the hydrophobic centers, to which it has little or no attraction. Water thus cannot penetrate the screen. Whatever the explanation, however, it is clear that the nonuniform, discontinuous, hydrophobic resinous deposits or centers are extremely effective in preventing moisture penetration into the metals.

This invention, its attributes and advantages, will be better understood by reference to the following illustrative examples, demonstrations and data.

In the following selected demonstrations and examples, a reduced iron product is obtained by charging a raw natural or nonspecular hematite ore to the top or initial stage of a reactor containing a series of four fluidized beds. The ore is progressively reduced, upon descent from one bed to the next of the series, by treatment with an ascending gaseous mixture of hydrogen and temperatures ranging from an initial 1400 F., to 1500" F. in the final fluidized bed. The particulate reduced iron product, 95 percent metallized, is withdrawn from the final stage of the reactor at 1430 F. Portions of the powder are compacted in a roll-type press to form briquettes of size (in inches) 3% x 2% x 1%, and portions of powder, per se, are treated with liquid olefin hydrocarbon (except as otherwise specified) of the following approximate chemical and physical composition:

Average carbon number C C Cyclodienes, wt. percent 7-10 Gravity, API (ASTM D 287-55) 10-13 Viscosity, SSU at 210 F. (ASTM D 88-53) 210-220 Flash, COC, F. (ASTM D 92-52) 280 Iodine number, cg./g. (ASTM D 555-54) 240-255 Ash, wt. percent 0.06 Nonvolatile matter, wt. percent (ASTM D 154- 53) 95 Color, Gardner (1 g. olefin in 67 ml. water white xylene) 10 Acid number, mg. KOH/g 0.1 Saponification number, mg. KOH/ g 3.18 Surface tension, dynes/cm. 44.5

Distillation at 10 mm. (ASTM D 1160), F.

IBP 182 (cracked) 504 EXAMPLES l3 Particulate metallized product withdrawn from the reactor is pressed between the rolls of a roll-type press to form briquettes of 25 to 30 percent porosity. The individual briquettes are broken apart from the issuing series by a string breaker, passed to a separate chamber and quenched in air to 400 F., 500 F., and 600 F., respectively. The briquettes, at these initial temperatures, respectively, are then dipped or immersed for 10 seconds in a bath of the olefinic liquid hydrocarbon, held at a constant temperature of 200 F., and the wetted briquettes then withdrawn, spread on a tray and dried for about 30 minutes in air.

To determine the effectiveness of the treating in preventing moisture penetration, comparisons are made between treated and untreated briquettes, subjected to identical, rather severe conditions wherein the briquettes are totally immersed for 5 to 10 minutes in water, and moisture determinations then made. The results are given in Table I. below.

TABLE I.B RIQUETTES OF 25-30% POROSITY [Dip time=10 seconds; bath temperature=200 F.]

Wt. percent water Wt. percent pickup Briquette dip olefin temperature, 1*. applied Treated Untreated Measured by soaking briquette in water at ambient temperature or 5-10 minutes.

In an additional run, 1300-1350 F. briquettes are quenched in a bath of the liquid olefinic hydrocarbons to which water is added in 1:1 weight conc. oilzwater ratio. After quenching the briquettes to about 600 F. in a 200 F. bath, a short air blast (800 f.p.m. for ca. 30 seconds) is used to drive off excess steam from the briquettes. The table below summarizes the data obtained:

, TABLE II Initial conditions:

1300-1350 F. briquettes.

25-30% porosity. Bath at 200 F. Quench time, seconds 5 Briquette surface temperature, after quench,

F. 550-600 Olefin deposition, wt. percent 0.8 Water pickup, wt. percent 0.2

1 Five-minute water immersion at ambient temperature.

Water pickup by the briquettes in the rigorous testing is generally less than 0.2 weight percent. In normal transportation and storage environments moisture penetration is less than 0.1 weight percent over a period of six months, with briquettes impregnated with 0.5 weight percent olefins. Penetration is fairly deep because briquettes, even after severe abrasion of the entire surface with a grinding wheel, show no increase in water pickup. Increased water pickup to about 0.5-1.0 weight percent is found after briquettes are completely shattered.

Tests show that undesirable smoking and burning during melting of the briquettes is within tolerable limits.

7 EXAMPLE Particulate metal or powder is cooled in an inert atmosphere of nitrogen to 600 F. and admixed with liquid olefinic hydrocarbon controlled at a temperature of 200 F. After seconds, a portion of the powder is still aircooled and a portion is force air cooled to ambient temperature. It is found that the piles retain about 0.1 weight percent of the liquid olefin hydrocarbons. Two additional portions of powder are cooled in nitrogen to ambient temperature without treatment with liquid olefinic hydrocarbon.

Four conical shaped piles, with indented apexes, are formed from the four portions of powder. It is found that the two piles of untreated powder will soak up water immediately and virtually instantaneously when water is dropped within the indented top surfaces. Drop after drop is soaked-up until the piles are completely wetted. In sharp contrast, drops of water stand as spheroids on the two piles of treated powder indicating that even powder is virtually completely moisture-proofed by the treatment.

EXAMPLE 6 Cold particulate ferrous metal is admixed with a Varsol solution (3 weight percent olefin in Varsol) of the liquid olefin hydrocarbon (10 weight percent Varsol solution, based on the weight of metal) and baked for 30 to 45 minutes at 400 F. The dried particulate metal is formed into piles and treated as in the foregoing example. As in the foregoing example, the piled metal is virtually completely moisture-proof. Drops of water stand as spheroids on the piles.

The results are striking and show the extremely high degree of effectiveness of these treatments. When powders or briquettes are piled in conical shape, water contacting the piles is shed, the water rolling down the outer surface as spherical shaped balls.

In analysis of the treated briquettes and powders formed pursuant to this invention, it is found that backoxidation is virtually eliminated. Hydrogen evolution, a measure of the degree of back-oxidation, is essentially nil. No spontaneous heating occurs in the piled materials. lIn short, the treated materials are rendered substantially chemically stable by the treatments.

Liquid olefin hydrocarbons suitable for the practice of this invention include partially polymerized acyclic and cyclic monoolefins, diolefins, and multiolefins, and preferably dimers, trimers and tetramers thereof, whether straight chained or branched chained and whether substituted or unsubstituted, to provide an average carbon number ranging from about C to about C50, and preferably from about C to about C Exemplary of such species of olefins are, e.-g., acrylic acid, methacrylic acid, ethyl acrylate, butene-l, butene-Z, Z-methyl-l-propene, pentene-l, ethyl methacrylate, polytetrafluoroethylene, isobutene, 3-methy1-1-butene, 3-hexene, 3-methyl-2-pentene, 3-ethyl-3-hexene, 3,3-dimethyl-2-ethyl-l-butene, 3,3,6-trimethyl-l-heptene, l-tridecene, 6-butyl-6-undecene, l-heptadecene, 9-octadecene, 2-methyl-1-nonadecene, pentaistobutylene, l-tetracosene, 9-octyl-8-heptadecene, heptaisobutylene, 17-pentriacontene, 1,4-butadiene, 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, 3-methyl-2,5- hexadiene, 6 methyl 1,4 heptadiene, 1,5 nonadiene, 3 -ethyl-1,5-octadiene, 1,10-undecadiene, 4-buty1-1,10-undecadiene, 2-methyl 2,14 tricosadiene, 1,3,5-hexatriene, dodecatriene, and the like, and dimers, trimers and tet ramers of such compounds. Illustrative of cyclic monoolefins, diolefins and multiolefins of such character are, e.g., 1,5-dimethyl-2-phenyl-3-pyrazolone, cyclopentadiene, 1,4-epoxy-l,3-butadiene, 1 thia 2,4 cyclopentadiene, 1-aza-2,4-cyclopentadiene, 1,2-benzofuran, thianaphthene, l-propyl 1 cyclopentene, 1-rnethy1-2-propyl-l-cyclopentene, l-amyl-l-cyclopentene, 1 decyl l cyclopentene, 1-hexadecyl-l-cyclopentene, 1 methyl 3 octadecyl-lcyclopentene, cyclohexene, 1,2,3-trimethyl-l-cyclohexene,

1-amyl-2-methyl-l-cyclohexene, cyclooctene, cyclopentadecene, cycloheptadecene, 1,2-cycloheptadiene, 1,3-cyclooctadiene, 1-methyl-4-ethyl-1,3-cyclohexadiene, l-methyl- 3-propyl-4-isopropyl 1,3 cyclohexadiene, 1,16-cyclotriacontadiene, 1,IO-dimethyl-1,l-6-cyclotricontadiene, 1,3,5- cyclo'heptatriene, 1,3,5-cyclooctatriene, and the like, and dimers, trimers and tetramers of such compounds.

Partial polymerization products, viz., dimers, trimers, tetramers, and the like, of these and other liquid olefin hydrocarbons, and reaction products of the same or different named molecular species and others are suitable in the practice of this invention. It is entirely unnecessary to use pure compounds. Commercial mixtures, residuals, plant side streams, and the like, which include mixtures of these and other compounds, can be readily utilized. Side streams and residuals from the same or different processes can be mixed together to provide suitable liquid olefin hydrocarbons.

A suitable commercial mixture of liquid olefin hydrocarbons is one obtained by steam cracking naphthas to obtain, after removal of unreacted naphtha and cyclopentadiene, an olefinic mixture of average carbon number ranging C to C or C to C and higher. This mixture is partially polymerized by contact, at from about 250 F. to about 350 F., with a low volatile matter acid clay (Attapulgus) to form olefins of average carbon number ranging from about C to C and preferably from about C to about C The mixture contains largely acrylic olefins, viz., monoolefins and diolefins, dimers, trimers, tetramers, and the like. While the mixture contains some cycloolefins, i.e., from about 1-3 percent by weight, the addition of cyclopolyenes and cyclodienes greatly enhances the utility of the stream for use in the process of this invention. Suitably from about 4 to about 7 percent by weight of additional cyclopolyenes is added to the mixture to form a mixture ranging from about 7-10 percent cyclopolyenes and cyclodienes. The mixture is heat-reactive and, because of the highly unsaturated character of the mixture (iodine number 220-255), it dries and cures on the metal surfaces to form resinous deposits within the capillary pores and crevices by both oxidation and polymerization.

It will be understood that the specific process described, and the products produced, can be modified to some extent without departing the spirit and scope of the present invention.

Having described the invention, what is claimed is: 1. A process for moisture-proofing metals comprising contacting the surface of the metal with a liquid olefin hydrocarbon of average carbon number ranging from about C to about C at metal surface temperatures ranging from about 400 F. to about 700 F., and higher,

maintaining the liquid olefin hydrocarbon during contact at temperatures ranging from about F. to about 300 F.,

maintaining contact between the liquid olefin hydrocarbon and the metal surface for time sufficient to cause the olefin to penetrate into the capillary pores and crevices of the metal in concentration ranging from about 0.05 percent to about 0.7 percent, based on the total weight of the impregnated metal,

withdrawing, drying and heat-curing to form discontinuous hydrophobic resinous deposits across the metal surface by virtue of which the metal becomes impervious to attack by moisture, corrosive gases, fumes and impurities.

2. The process of claim 1 wherein the liquid olefin hydrocarbon is an admixture of olefins and diolefins, including cyclopolyenes and cyclodienes, and the average carbon number ranges from about C to about C 3. The process of claim 2 wherein the mixture of liquid olefin hydrocarbons contains from about 7 percent to about 10 percent cyclodienes, based on the weight of the mixture.

4. The process of claim 1 wherein the viscosity of the olefinic liquid hydrocarbon is maintained between about 100 SSU and 250 SSU.

5. The process of claim 1 wherein a diluent is added to the liquid olefin hydrocarbon.

6. The process of claim 5 wherein the diluent is a dialkyl sulfoxide.

7. The process of claim 6 wherein the diluent is dimethyl sulfoxide.

8. The process of claim 5 wherein the diluent is selected from aromatic, paraflinic, and chlorinated hydrocarbons, acetates, ketones and high molecular weight alcohols.

9. The process of claim 1 wherein the temperature of the metal surface ranges from about 500 F. to about 600 F.

10. The process of claim 1 wherein the temperature of the undiluted olefin hydrocarbon at the time of contact with the metal ranges from about 150 F. to about 200 F.

11. The process of claim 1 wherein the olefin which has penetrated into the capillary pores and crevices is cured by heat treatment at temperatures ranging from about 50 F. to about 300 F., for a period of time ranging from about 5 minutes to about 60 minutes.

12. The process of claim 1 wherein the moistureproofed metal is a ferrous metal.

13. The process of claim 12 wherein the ferrous metal is one resultant from a direct iron ore reduction process.

14. The process of claim 13 wherein the metal is powder, and resultant from a fluidized iron ore reduction process.

15. The process of claim 14 wherein the product is briquetted, and contains from about 80 percent to about 95 percent metallic iron, the balance thereof consisting essentially of iron oxides.

16. The process of claim 13 wherein the ferrous metal contains from about 1 percent to about 8 percent carbon.

17. In a direct iron ore reduction process wherein iron ore is reduced at temperatures ranging from about 1000 F. to about 1800 F., and withdrawn as a metallized product, the improvement comprising quenching the product with an emulsion of water and liquid olefin hydrocarbons of average carbon number ranging from about C to about C to reduce the temperature of the product to below about 600 F., to cause penetration of the olefin into the pores of the metal, and then drying and heatcuring to form discontinuous hydrophobic resinous deposits across the metal surface by virtue of which the metal becomes impervious to attack by moisture, corrosive gases, fumes and impurities.

References Cited UNITED STATES PATENTS 3,511,718 5/1970 Segura 117-100 3,498,958 3/1970 Chaudhuri et a1. 117-127 3,481,768 12/1969 Gowdy 117-400 ALFRED L. LEAVITT, Primary Examiner M. F. ESPOSITO, Assistant Examiner US. Cl. X.R. 

